you have districts voting for president obama, districts voted against president obama, in the house, more sorting, fewer legislators, either chamber, elected from chambers who voted for the other party for president, you have a consistent line of political direction, you have republicans from constituent says that really aren't looking for them to compromise overwhelmingly, and democrats the same is. the problem is that while that make senses for any individual legislator, no way to run a country divide ready. in the end, both sides have to give. democrats have to look at more entitlement changes the long run, no other reason it will squeeze all out the discretionary spending, the investment is in the future they prefer. republicans also have to kind of understand that we did have an election focus on this issue whether we were going to tax people at the top more. president obama did win 51% of the vote, almost certainly going to happen. as i say you can the problem is for each individual politician, less incentive to compromise, their constituency leans more heavily toward one side